STANDARD Physics Alternating Current Class 12 Questions

Alternating current cannot be measured by DC ammeter because

A 100 Ω resistor is connected to a 220 V, 50 Hz ac supply. The rms value of current in the circuit is

The relation between an ac voltage source and time in SI units is V = 120 sin(100 πt) cos(100 πt) V. The value of peak voltage and frequency will be respectively

An ac source is of 200/√2 V, 50 Hz. The value of voltage after 1/600 s from the start is

If V = 100 sin(100t) V and I = 100 sin(100t + π/3) mA are the instantaneous values of voltage and current, then the rms values of voltage and current are respectively

In an ac circuit, V and I are given by V = 150sin(150t)V and I = 150sin(150t + π/3) A. The power dissipated in the circuit is

The phase relationship between current and voltage in a pure resistive circuit is best represented by

In the case of an inductor

A 44 mH inductor is connected to 220 V, 50 Hz ac supply. The rms value of the current in the circuit is

The graphs given below depict the dependence of two reactive impedances X₁ and X₂ on the frequency of the alternating e.m.f. applied individually to them. We can then say that:

Frequency of A.C. in India is -

Given below are two statements. Statement I: In an ac circuit, the current through a capacitor leads the voltage across it. Statement II: In a.c circuits containing pure capacitance only, the phase difference between the current and the voltage is π. In the light of the above statements, choose the most appropriate answer from the options given below:

A series LCR circuit with inductance 10 H, capacitance 10 μF, resistance 50 Ω is connected to an ac source of voltage, V = 200 sin(100t) volt. If the resonant frequency of the LCR circuit is v₀ and the frequency of the ac source is v, then

At resonance in a series LCR circuit, which of the following statements is true:-

Which of the following combinations should be selected for better tuning of an L-C-R circuit used for communication?

In an alternating current circuit consisting of elements in series, the current increases on increasing the frequency of supply. Which of the following elements are likely to constitute the circuit?

A 60 μF capacitor is connected to a 110 V, 60 Hz AC supply. The rms value of current in the circuit is

In which of the following circuits the maximum power dissipation is observed?

In the circuit shown in figure, what will be the reading of the voltmeter?

In the series LCR circuit shown, the impedance is

A circuit containing a 20 Ω resistor and 0.1 μF capacitor in series is connected to 230 V ac supply of angular frequency 100 rad s⁻¹. The impedance of the circuit is

In series LCR circuit, the phase angle between supply voltage and current is

In a series ICR circuit the voltage across an inductor, capacitor and resistor are 20 V, 20 V and 40 V respectively. The phase difference between the applied voltage and the current in the circuit is

The resonant frequency of a series LCR circuit with L = 2.0 H, C = 32 μF and R = 10 Ω is

The Q factor of a series LCR circuit with L = 2 H, C = 32 μF and R = 10 Ω is

Power dissipated in an LCR series circuit connected to an ac source of emf ε is

A series LCR circuit with R = 22 Ω, L = 1.5 H and C = 40 μF is connected to a variable frequency 220 V ac supply. When the frequency of the supply equals the natural frequency of the circuit, what is the average power transferred to the circuit in one complete cycle?

The power factor of the circuit as shown in figure is

A resistor of 500 Ω and an inductance of 0.5 H are in series with an ac source which is given by V = 100√2 sin(1000t). The power factor of the combination is

In a series LCR circuit, the phase difference between the voltage and the current is 45°. Then the power factor will be

In an electrical circuit, R, L, C and ac voltage source are all connected in series. When L is removed from the circuit, the phase difference between the voltage and the current in the circuit is π/3. If instead, C is removed from the circuit, the phase difference is again π/3. The power factor of the circuit is

An inductor of reactance 1 Ω and a resistor of 2 Ω are connected in series to the terminals of a 6 V (rms) ac source. The power dissipated in the circuit is

The voltage across a pure inductor is represented in figure. Which one of the following curves in the figure will represent the current?